text: The metal chloride solution (in the most common case waste pickle liquor from a carbon steel pickling line) is fed to the venturi evaporator (III), where direct mass and heat exchange with the hot roast gas from the roaster (reactor/cyclone) takes place. The separator (IV) separates the gas and liquid phase of the venturi evaporator product. The liquid phase is re-circulated back to the venturi evaporator to increase mass and heat exchange performance.
  * approx. 25 to 30% of the waste acid (HO, HCl) are evaporated
  * roast gas is cooled down to approx. 92 to 96 °C
  * dust particles are removed from the roast gas